1. Field
This disclosed embodiment pertains to the field of passenger seats such as the seats used in passenger spaces in vehicles and, more specifically, in aircraft.
The disclosed embodiment concerns a seat convertible into a bed and including, between the “seating” position and the “lying” position, an intermediate position for “resting”, in which the passenger is placed in a relaxing position.
More specifically, in the disclosed embodiment, the layout of the structure of the seat allows continuous modification of the position of the seat cushion and the position of the backrest between the seating and lying positions, ensuring passenger comfort when the seat is in the intermediate, resting position.
2. Brief Description of Related Developments
In the field of passenger transport, in particular in aircraft, the seats offered to passengers are equipment with high commercial impact.
Airlines which operate aircraft are therefore demanding in terms of the comfort offered to passengers, but also remain concerned with the cost of the equipment, both with regard to its purchase and its maintenance.
In the luxury classes, first class and business class, aircraft cabin seats are, in general, capable of being converted in order to transform the seat from the seated position, required during takeoff and landing, to a lying position that is nearly horizontal.
In order to convert from a seated position to a lying position, the seat bottom is generally moved forward by sliding or rolling on rails, generally by means of a first engine, and the seat back is inclined backward, until it is close to aligned with the seat bottom, by means of a second engine.
In this conversion, forward movement of the seat is necessary so that the inclined seat back does not intrude into the volume of space located behind the seat, which is in general allocated to another passenger, and is often blocked by a fixed covering shell.
A disadvantage of this solution is the lack of comfort when the seat is in an intermediate, resting position, where the seat back is only partially inclined toward the back.
This solution, which, in practice, only affects the angle formed at the lumbar vertebrae of the spine, leads to the passenger sliding forward, a phenomenon also known as “submarining” when the passenger tends to slide under the seat located in front of his.
In order to avoid this sliding phenomenon, one solution consists of raising the front of the seat bottom when the seat back is inclined backward so that the surface of the seat bottom is inclined backward and prevents the natural tendency of the passenger to side forward. In this case, the front edge of the seat bottom moves away from the floor and the passenger's feet, in many cases, are no longer in contact with the floor to which the seat is attached. This configuration, the purpose of which is to improve comfort, quickly becomes uncomfortable due to the compression felt by the passenger in the popliteal hollows.
In addition, this supplementary movement of the seat bottom requires the installation of an additional actuator, which hinders attainment of the generally desired goals of decreasing the weight and cost of a seat.